Conventional steel wheels for automobiles are relatively inexpensive, but generally do not have an aesthetically pleasing appearance, and can detract from the appearance of the automobile. To conceal the mounting studs and nuts, painted or chromed hub caps have been snap fitted over the central hub portion of the wheel. While these make some improvement to the appearance of the wheel, their big disadvantage is that they are readily detachable and can easily be stolen or inadvertently come off during operation of the vehicle.
During more recent years, so called non-ferrous "mag" wheels have become more popular, and apart from any technical and performance reasons, these "mag" wheels have become a prestige symbol and are considered by many to add class and distinction to a vehicle. However, such wheels are considerably more expensive than standard steel wheels.
In an attempt to improve the appearance of standard steel wheels, give them more distinctiveness and prestigeous appeal, and yet keep the cost below that of genuine "mag" wheels, several approaches have been tried or suggested.
One of these suggestions has been to mold a decorative plastic overlay on the outboard side of the wheel and finish this overlay to appear like metal. There are several disadvantages to this approach. These concern the inconvenience and cost of handling the steel wheels during the molding process; the thickness of the plastic necessary to obtain some outboard contours and appearances, particularly if a "mag" wheel shape is intended; and the damage the surface of the plastic overlay can sustain during handling, for example during tire changing. However, a main disadvantage is that once the wheel has been manufactured, its shape and appearance cannot be changed. Consequently, if a number of different shapes and appearances are in demand, as they usually are, then it is necessary for the manufacturer and distributor to stock all these different shapes. Apart from increasing the inventory of wheels required, this also has the effect of limiting the number of optimal shapes and appearances that are available.
Another proposal has been to provide an imitation "mag" wheel by applying a thin decorative cover over the entire outboard side of a conventional steel wheel, including the tire supporting rim, and securing the cover in place by engaging its outer periphery over the outer periphery of the tire supporting rim and clamping the central portion to the wheel center by means of the wheel mounting studs and nuts. Although this would appear to be a fairly inexpensive approach to improving the appearance and appeal of a conventional steel wheel, it still has some shortcomings. Firstly, the cover would tend to be permanently attached to the steel wheel and could not easily be changed. Secondly, the outer periphery portion of the cover, engaging over the periphery of the tire rim, would risk getting damaged during tire mounting and changing operations. Thirdly, this same decorative portion would be exposed to damage during vehicle operation if, for example, the wheel scraped against a curb or the like. And, fourthly, it would appear necessary to have the cover nest fairly closely to the outboard contour of the wheel center, so placing a limitation on the types of contours and appearances that could be obtained.